Re: Wow! Is memory ever cheap!

From: Larry McVoy (lm@bitmover.com)
Date: Sat May 05 2001 - 21:45:36 EST


On Sun, May 06, 2001 at 02:20:43PM +1200, Chris Wedgwood wrote:
> 1.5GB without ECC? Seems like a disater waiting to happen? Is ECC
> memory much more expensive?

Almost twice as expensive for 512MB dimms.

I used to be a die hard ECC fan but that changed since what we do here is
BitKeeper and BitKeeper checksums everything. It tells us right away when
we have problems (to date it has found bad memory dimms, NFS corruption,
and a SPARC/Linux cache aliasing bug). So I've given up in ECC, we don't
need it.

On the other hand, if your apps don't have built in integrity checks then
ECC is pretty much a requirement.

By the way, the integrity checks don't need to be complicated, BK uses
a horrible 16 bit ignore the overflow checksum to be compat with SCCS
and it seems to have caught everything that much more sophisticated and
CPU intensive checksums have caught. In other words, anything is much
much better than nothing.

-- 
---
Larry McVoy            	 lm at bitmover.com           http://www.bitmover.com/lm 
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Mon May 07 2001 - 21:00:23 EST